The preferred embodiment relates to Publish/Subscribe (pub/sub) systems and more particularly to the controlled processing of published messages in such systems.
A Publish and Subscribe (pub/sub) system is an effective way of disseminating information to multiple users. Pub/Sub applications can help to simplify the task of getting business messages and transactions to a wide-spread, dynamically changing and potentially large audience in a timely manner.
In a pub/sub system, publishers are not concerned with where their messages go and subscribers are not interested in where the messages they receive have come from. Instead, a broker typically assures the integrity of the message source and manages the distribution of a message according to subscriptions registered in the broker.
Ordinarily, a published message is delivered to subscribers in the same form it had when originally published. There is a need for flexibility such that a message can be modified after its original publication and before delivery to a final subscriber.